The present invention generally relates to technology for supporting the construction of a configuration related to a backup executed by a storage system.
Technology for backing up data (for convenience sake, referred to as “source data” hereinafter) in preparation for a failure or human error that results in the loss of source data is being widely applied in computer systems.
One known backup method involves creating a replicate (hereinafter, replicated data) at a certain time for backup-targeted source data, and storing this replicated data in a storage extent (for example, in a secondary logical volume that constitutes a pair with a primary logical volume, hereinafter referred to as “SVOL”) that is different from the storage extent in which the source data is stored (for example, a primary logical volume, hereinafter referred to as “PVOL”). Replicated data is either created regularly on the basis of a preset schedule, or is created as deemed necessary in accordance with a user indication.
Further, another known backup method conforms to CDP (Continuous Data Protection) technology, which makes source data at an arbitrary point in time recoverable for a certain limited period of time. In this technology, information denoting a history related to the updating of source data (hereinafter, a journal) is acquired at source data updating, and this journal is stored in a storage extent that is different from the PVOL (for example, a logical volume, hereinafter referred to as “JVOL”). A replicate of the source data of prior to journal acquisition (hereinafter, “base data”) is also created, and this is stored in a storage extent that is again different from the storage extent in which the source data and journal are stored (for example, a logical volume, hereinafter referred to as “BVOL”). When a data recovery request specifying an arbitrary specified time is received, one or more journals acquired from the BVOL creation time (base data acquisition time) up to this specified time are reflected in order in the BVOL, thereby recovering the source data of the specified time inside the BVOL (That is, the base data is updated to the source data of the specified time.).
To construct a backup configuration in a storage system for carrying out a backup using a backup method, which conforms to CDP technology (hereinafter, a CDP configuration), it is necessary to design beforehand a data protection period (a period from a prescribed time to the oldest time at which data is recoverable) and a JVOL storage capacity. Japanese Patent Laid-open No. 2007-140746 discloses technology for computing the required JVOL storage capacity based on user design conditions (target recovery point, target recovery time, journal storage period, and so forth) and measured data regarding the write status of the data.
However, in a storage system that is already in operation, it is assumed that some sort of backup method already exists prior to constructing a new backup configuration (for example, a CDP configuration). Determining the propriety of migrating from an existing backup method to another backup method is difficult. Japanese Patent Laid-open No. 2007-140746 discloses CDP configuration design technology, but does not offer a disclosure related to determining whether or not it is appropriate to migrate from an existing backup configuration to the CDP configuration.